ABSTRACT
Objective To analyze the clinical features of juvenile-onset clinically amyopathic dermatomyositis complicated by progressive interstitial pneumonia.Methods A retrospective analysis of a case of juvenile-onset clinically amyopathic dermatomyositis on clinical features,diagnosis and treatment was performed.Data of the other three reported cases were also reviewed.Results The patient was an adolescent girl presented with Gorrton's sign.The patient did not have fatigue and got normal result in creatine kinase and elctromyogram test.The HRCT exam showed interstitial pneumonia.The mean age of the four cases at the time of onset is 12.3 years old.Gottron's sign (3/4) and fever (2/4) are the most common symptoms of onset.Anti-nuclear antibody (ANA),anti-Jo-1 antibody are 100％ negative in the four patients.Two of the four patients who received anti-Ro-52 antibody test are both positive.Three of the four patients were asymptomatic when the CT scan showed interstitial pneumonia.The interstitial pneumonia was progressive and three of the four patients died of respiratory failure within six months.Treatment with glucocorticoid and immunosuppressant was successful in one case.Conclusions Juvenile CADM can be complicated by progressive interstitial pneumonia.Children suspected CADM should perform pulmonary imaging examinations to find interstitial pneumonia.Children diagnosed as CADM complicated by interstitial pneumonia should receive glucocorticoid and immunosuppressant treatment to prevent progression.